Gas Turbine Engine Systems Involving Variable Nozzles with Sliding Doors

ABSTRACT

Gas turbine engine systems involving variable nozzles with sliding doors are provided. In this regard, a representative door assembly for a gas turbine engine includes: a door configured for alignment with an exit area of a nozzle and operative to variably open and close the nozzle exit area such that gas directed along a gas path defined, at least in part, by the nozzle exit area is regulated

BACKGROUND

1. Technical Field

The disclosure generally relates to gas turbine engines.

2. Description of the Related Art

Varying the nozzle exhaust area of a gas turbine engine can affect engine performance. By way of example, varying the nozzle exhaust area can alter propulsive efficiency, fan stability, noise output, and/or fuel consumption.

SUMMARY

Gas turbine engine systems involving variable nozzles with sliding doors are provided. In this regard, an exemplary embodiment of a door assembly for a gas turbine engine comprises: a door configured for alignment with an exit area of a nozzle and operative to variably open and close the nozzle exit area such that gas directed along a gas path defined, at least in part, by the nozzle exit area is regulated.

An exemplary embodiment of a nozzle assembly for a gas turbine engine comprises: a nozzle defining a nozzle exit area; and a door operative to selectively increase and decrease an effective size of the nozzle exit area.

An exemplary embodiment of a gas turbine engine comprises: a compressor; a turbine operative to drive the compressor; and a nozzle assembly positioned downstream of the turbine, the nozzle assembly defining an exit area and having a door operative to move between an open position, at which the nozzle assembly exhibits a maximum exit area, and a closed position, at which the nozzle assembly exhibits a minimum exit area.

Other systems, methods, features and/or advantages of this disclosure will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features and/or advantages be included within this description and be within the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic diagram depicting an exemplary embodiment of a gas turbine engine.

FIG. 2 is a cross-sectional perspective diagram of the gas turbine engine of FIG. 1.

FIG. 3 is a perspective diagram depicting an exemplary embodiment of a nozzle assembly.

FIG. 4 is a schematic diagram depicting the sliding door of the embodiment of FIG. 3 in a planar view.

DETAILED DESCRIPTION

Gas turbine engine systems involving variable nozzles with sliding doors are provided, several exemplary embodiments of which will be described in detail. In some embodiments, such a sliding door is moved fore and aft in a gas turbine engine to vary the nozzle exhaust area of the engine dynamically. Varying the nozzle exhaust area in a gas turbine engine can increase engine performance characteristics such as fuel efficiency.

FIG. 1 is a schematic diagram depicting an exemplary embodiment of a gas turbine engine 100 in which a nozzle assembly 10 that incorporates a sliding door can be used to operatively vary the exit area 14 of the nozzle assembly 10 and affect engine performance. FIG. 2 is a cross-sectional perspective diagram of the gas turbine engine depicted in FIG. 1. As shown in both FIG. 1 and FIG. 2, the gas turbine engine 100 includes a compressor section 102, a combustion section 104, a turbine section 106, and an exhaust section 108. It should be noted that although engine 100 is a turbofan engine, there is no intention to limit the concepts to use with turbofan engines as other types of gas turbine engines can be used.

The exhaust section 108 of gas turbine engine 100 includes nozzle assembly 10, which defines an exit area 14. In operation, gas is routed along a gas path 26, which passes through duct 16 to the nozzle assembly 10, and then out of the nozzle assembly via exit area 14. Performance of the gas turbine engine 100 can be affected by regulating gas directed along gas path 26 by influencing the gas in a vicinity of the exit area 14.

In this regard, reference is made to the perspective diagram of FIG. 3, which depicts nozzle assembly 10 and the incorporated sliding door 12. As shown in FIG. 3, sliding door 12 is configured to be translated across exit area 14 and thereby influence gas directed along gas path 26. In at least one embodiment, the nozzle assembly is a third stream exhaust nozzle that is operative to regulate gas accelerated by a tertiary fan (e.g., a tip fan located radially outboard of a fan stage). A third stream nozzle helps enable the engine variable cycle. By way of example, by closing the third stream nozzle area, the third stream duct experiences increased backpressure and the fan air normally flowing into the third stream duct diverts into the secondary/primary flow stream. Notably, the flow streams communicate just aft of the fan. A third stream splitter, which can be located several inches aft of the fan, for example, leaves a large enough area for effective flow stream communication. However, in other embodiments, a nozzle assembly can be used for varying the flow characteristics of gas directed along one or more other gas paths.

The sliding door 12 is configured to be variably positioned along a range of positions between a full open position, at which the nozzle assembly 10 exhibits a maximum exit area, and a full closed position, at which the nozzle assembly 10 exhibits a minimum exit area. As the sliding door 12 is variably positioned, gas directed along gas path 26 is regulated.

In the embodiment of FIG. 3, sliding door 12 exhibits a low section area relative to a direction of travel associated with gas directed along gas path stream 26. Such a configuration and orientation tends to result in a low actuation load, i.e., the load required to be overcome for positioning of the door. In this regard, the nozzle assembly 10 also incorporates an actuator 20 that engages sliding door 12. The actuator 20 is attached to the sliding door 12 and is configured to operatively translate the sliding door 12 in both a fore and aft direction, as indicated by arrows 18.

By way of example, the actuator 20 can be an air motor driven direct actuated ball screw ram, direct actuated hydraulic ram, and air or hydraulic driven mechanisms. Actuator 20 may be singular or a plurality of synchronized actuators. For example, the actuator 20 includes air motor driven direct actuated ball screw rams (such as linear motion cylindrical actuators or rotary motion actuators), synchronized via flex drive cables (a commonly used actuation configuration in various commercial nacelle reverser cowlings). The actuator 20 can be located unobtrusively in an area 30 of the nozzle assembly 10 between gas path 26 and a core path 24.

In some embodiments, a nozzle assembly can also incorporate a pressurized plenum. Such a pressurized plenum can be configured to provide pressure balancing to the nozzle assembly thereby reducing actuation loads. If the loads are predicted to be reacted primarily by the tracks, a plenum may not be required. However, when a plenum is utilized (such as in association with area 30 in this embodiment), the plenum can be a direct acting plenum placed, for example, on the forward facing face of the door. Alternatively, a remote balance chamber can be utilized.

The nozzle assembly 10 also incorporates a rail 22 for the sliding door 12. The rail 22 facilitates the translation of the sliding door 12. In particular, the rail 22 provides a track on which the sliding door 12 is translated. The rail 22 also is configured to provide alignment and structural stability to the sliding door 12. In at least one embodiment, more than one rail 22 is utilized. In other embodiments, the rail 22 includes one or more bearings to facilitate a smoother translation of the sliding door 12 along the rail 22. In yet another embodiment, the tracks of the rail 22 can be embedded in the fixed structure ahead of the door 12, and/or along sides of the door, such that that door 12 is cantilevered aft and the tracks are hidden from the flowpath.

The nozzle assembly 10 also incorporates a plurality of stiffening ribs 28 to control deflection of the sliding door as the sliding door 12 is variably opened and closed. For example, as the sliding door 12 is variably closed, pressure increases within the duct 16. The plurality of stiffening ribs 28, located behind the interior wall of the duct 16, reduces deflection of the interior wall. The plurality of stiffening ribs 28 also provides structural support to the sliding door 12 as the door translates across the exit area 14 of the nozzle assembly 10.

FIG. 4 is a schematic diagram depicting the nozzle assembly 10 of FIG. 3. As shown in FIG. 4, the gas path 26 includes passage through duct 16, the nozzle assembly 10 and exit area 14.

The actuator 20 is connected to the sliding door 12 and is configured to operatively translate the sliding door 12 in both a fore and aft direction, as indicated by arrows 18, thus varying the exit area 14 of the nozzle assembly 10. In operation, the sliding door 12 is variably opened and closed, by translating in both a fore and aft direction, as indicated by arrows 18. In other embodiments, more complex motion of the sliding door can be used. Regardless of the particular motion involved, positioning of the door varies the exit area 14 of the nozzle assembly 10 and thereby affects one or more of various engine performance characteristics.

It should be emphasized that the above-described embodiments are merely possible examples of implementations set forth for a clear understanding of the principles of this disclosure. Many variations and modifications may be made to the above-described embodiments without departing substantially from the spirit and principles of the disclosure. By way of example, in some embodiments, a sliding door can be configured to alter a nozzle throat asymmetrically in order to affect yaw vectoring of the flow. In some embodiments, this can be accomplished by the use of differential actuation of multiple actuators. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the accompanying claims. 

1. A door assembly for a gas turbine engine, the door assembly comprising: a door configured for alignment with an exit area of a nozzle and operative to variably open and close the nozzle exit area such that gas directed along a gas path defined, at least in part, by the nozzle exit area is regulated.
 2. The door assembly of claim 1, further comprising: an actuator connected to the door, the actuator being operative to translate the door such that the nozzle exit area is altered.
 3. The door assembly of claim 2, wherein the actuator is operative to translate the door in both fore and aft directions.
 4. The door assembly of claim 1, further comprising: a rail operative to engage the door such that engagement of the door and the rail facilitates alignment of the door with the nozzle exit area.
 5. A nozzle assembly for a gas turbine engine, the nozzle assembly comprising: a nozzle defining a nozzle exit area; and a door operative to selectively increase and decrease an effective size of the nozzle exit area.
 6. The nozzle assembly of claim 5, further comprising: an actuator connected to the door and operative to position the door such that the effective size of the nozzle exit area is established.
 7. The nozzle assembly of claim 6, wherein the actuator is operative to translate the door in both fore and aft directions.
 8. The nozzle assembly of claim 6, wherein the nozzle is a third stream exhaust nozzle.
 9. The nozzle assembly of claim 5, further comprising: a rail engaging the door and operative to provide alignment of the door during positioning.
 10. The nozzle assembly of claim 5, further comprising: at least one stiffening rib contacting the door and operative to provide structural support to the door.
 11. A gas turbine engine comprising: a compressor; a turbine operative to drive the compressor; and a nozzle assembly positioned downstream of the turbine, the nozzle assembly defining an exit area and having a door operative to move between an open position, at which the nozzle assembly exhibits a maximum exit area, and a closed position, at which the nozzle assembly exhibits a minimum exit area.
 12. The gas turbine engine of claim 11, further comprising an actuator connected to the door and operative to position the door.
 13. The gas turbine engine of claim 12, wherein the actuator is operative to translate the door in both fore and aft directions.
 14. The gas turbine engine of claim 11, wherein the nozzle assembly is a third stream exhaust nozzle assembly.
 15. The gas turbine engine of claim 11, further comprising at least one stiffening rib operative to provide structural support to the door.
 16. The gas turbine engine of claim 15, wherein the at least one stiffening rib is located on a non-gas path side of the door.
 17. The gas turbine engine of claim 11, further comprising a rail operative to provide alignment of the door.
 18. The gas turbine engine of claim 11, wherein the engine is a turbofan gas turbine engine.
 19. The gas turbine engine of claim 11, wherein the door is operative to symmetrically affect the gas path with respect to yaw.
 20. The gas turbine engine of claim 11, further comprising a plenum located on a non-gas path side of the door, the plenum being operative to pressurize in order to reduce an actuation load of the door. 